Now, according to an article at Technology Review, another old technology, for a type of Diesel engine, is getting another look. The basic design, called the Jumo engine, was originated back in the 1930s by Junkers, a German aircraft manufacturer. It was dirty, but very efficient. In contrast to a conventional Diesel engine, which uses a single piston per cylinder to compress air and fuel, the Jumo engine uses two pistons per cylinder, compressing the air-fuel mixture between them. The efficiency advantage arises from expending less energy heating up the cylinder head, leaving more to drive the pistons.

A California company called Achates Power has updated the engine design to allow it to meet current emission standards, at least in a one-cylinder prototype. The US Army has given Achates, together with a partner company, AVL Powertrain Engineering, a $4.9 million grant to develop a multi-cylinder prototype. The company believes that the engine can be made smaller and cheaper than existing Diesel engines, while boosting fuel economy by 20%. Compared to a gasoline engine, the fuel economy would of course look even better.

This is still a prototype, and the new design is not likely to make the 2014 model year for new cars. Still, it is encouraging that progress can be made without requiring a “great leap forward” in every instance.

Mozilla has released an updated version, 18.0.1, of its Firefox browser for Windows, Linux, and Mac OS X. This appears to be a bug fix release, focused on three specific areas:

Problems with HTTP Proxy transactions

Unity player crashes on Mac OS X

Rendering problems with HIDPI support on external monitors

There are no security-related fixes listed. More information is available in the Release Notes.

You can get the new version using the update mechanism built into the browser, either automatically or via Help / About Firefox / Check for Updates. Alternatively, you can get a complete installation package, available in more the 70 languages, from the download page.